Southern Elephant Seals - Mirounga leonina

Elephant seals are the largest of all seals, they show a
strong sexual dimorphism (difference in size between the males
and females). A fully grown male and female side by side are
commonly mistaken for an adult and juvenile.

southern Elephant Seal Basics

Breeding Season: Pups born
from September to October shortly after the arrival of pregnant
females on the birthing beach. The pups are nursed for about
three weeks after which the mother goes to sea at which
point the pup is weaned, the pups remain on the breeding
beach for 8-10 weeks before going to sea. Females mate a
few days before the pup is weaned, there is probably an
implantation delay and then the female is pregnant.

Estimated world population: - 650,000
in the mid 1990's no more recent worldwide estimate is available.

Feeding & diet: Mainly squid, but also fish,
especially Notothenids known as "Antarctic cod",
about 75% squid to 25% fish. Males and females tend to feed
separately with males going further south pursuing bottom
dwelling (benthic) prey, females don't go so far south and
fish for prey in the mid-water (pelagic) zone.

Diving: Southern Elephant Seals are impressive
divers, regularly going down to 300-500m for a duration
of 20-30 minutes. A record depth of 1430m was attained by
a female with another recording a time underwater of an
incredible 120 mins, the longest ever recorded for any seal.

Conservation status: Least concern.
Protected by the Antarctic Treaty and the Convention for
the Conservation of Antarctic Seals.Distribution:
Circumpolar, though they are found throughout Antarctica
in low numbers down to the deep south, they are most numerous
north of seasonably variable pack ice in sub-Antarctic waters
and on sub-Antarctic islands, they are found as far north
as the Falkland Islands and the Peninsula Valdes at 42°S.

Predators: Killer whales, large sharks
in the more northern parts of the range, Leopard seals also
sometimes kill elephant seal pups.

What are Southern Elephant
Seals like?

There are two species of elephant seals in
the world, the Northern Elephant Seal that is found in the eastern
and northern Pacific Ocean and the Southern Elephant seal that
is found almost circumpolar around Antarctica. The
Southern Elephant seal is the largest of all the world's seal
species, southern males are up to 50% heavier and females 20%
heavier than their northern counterparts. They are enormous
animals that regularly reach 2,000 kg and may weigh up to 4
tonnes (8 800lb).

Southern Elephant seals show
a very strong example of sexual dimorphism (a physical difference
between the males and females), Males may be up to ten times
the weight of reproductive females, only the very largest
males will reproduce which is about 2-3% of all males. A fully
grown male and female side by side are commonly mistaken for
an adult and juvenile, the picture to the right shows a fully
grown male and female.

They are called elephant seals partly because of their size
and also partly because of the males snout or trunk that he
inflates to impress and intimidate rivals when competing with
other males. The trunk is inflated with air and a loud bellowing
sound is made, the depth and volume of the sound being a way
of the male demonstrating to others how big and strong he is,
so avoiding fights with obviously smaller and weaker males.

Southern Elephant Seal
Breeding and Mating

Like some other species of seals, Elephant
seals (both northern and southern) breed in a "harem"
system. Females arrive in the spring at a beach where
she herself was probably born, this leads to a build up of numbers
of females and pups in these locations. Many seals have something
called delayed implantation whereby after mating, the embryo
rather than implanting into the womb lining goes into a sort
of stasis phase, so delaying the onset of pregnancy proper.
By these means, these usually very widespread seals can assemble
together at a beach where for the only reliable time in the
year, there will be reproductive males and females together.

The scene is therefore set for the males to compete
with each other for mating access to the females. Only the very
largest, most aggressive, most tenacious and strongest males
will win.

On elephant seal breeding beaches (they prefer gently sloping
beaches where they can leave the sea easily) the largest male
is called the "beach master" and he will defend his
harem of females for 24 hours a day without rest or feeding
during the breeding season. Fights are actually quite rare,
the males usually size each other up quite accurately and settle
the matter by bellowing and rearing up. Only when two of the
largest males are closely matched does a fight result. This
consists of them lifting themselves up and throwing all the
weight they can muster (and it's a lot of weight!) at the opponent.
Such fights can be very bloody and exhausting though serious
or permanent damage is rare, there is a very significant layer
of blubber to take the blows.

An individual male will usually only have one breeding
season where he is large enough and strong enough to become
beach master. The constant wakefulness, attention, elevated
stress hormone levels, fights and lack of food mean that he
is unlikely to be as in good condition for a second year. After
breeding males play no more part in the rearing of any pups,
the females by this means, assure that their pups are fathered
by the strongest and fittest males only.

The picture above is of a male who has sustained damage to
his trunk during a fight. This makes him less able to compete
with rival males and so he was master of a very small harem
of 2 or 3 females rather than up to a hundred that the biggest
and strongest males can command, he did however come back to
the same small beach to breed for several years as he was not
so stressed with defending a much bigger harem against many
more opponents.

Is all elephant seal life
aggressive?

Not at all, the breeding season is quite short, for
much of the year elephant seals spend their time at sea not
really associating with any other seals, they do come
ashore at some favourite and much used beaches to moult when
they form associations called "pods". Pods
are extremely smelly places. If the wind is towards you, you
know you are coming up to an elephant seal pod long before you
see it! A diet largely consisting of squid doesn't do much
for the state of your digestive system or your breath, you really
don't want to be breathed on by an elephant seal.

Most of the time pods are quite fairly restful places in
a constant snoring and guttural grumbling sort of way, but every
now and then one of the inner most seals decides it wants to
go to sea. Two tonnes or more of seal lumbering across his sleeping
companions causes quite a commotion.

Elephant seals spend only a small amount of their time on
land. Ashore they are cumbersome and great ungainly beasts,
in the water like many aquatic animals, they become lithe and
graceful with the blubber that made them ungainly on land becoming
essential as insulation and serving to give them a smooth torpedo
shaped outline making them very streamlined.

What are young elephant
seals like?

Elephant seal pups are born in the Antarctic spring.
Like many Antarctic seal pups, they stay with their mother increasing
rapidly in weight while the mother gets progressively thinner,
this happen for about three weeks and then the mother leaves
to go to sea and leaves the pup behind.

That's
about as far as parental care goes with Southern Elephant Seals.
The pups are very dark at birth and have quite delicate flippers
with long elegant nails that they scratch themselves with quite
precisely. If Weddell seal pups are big mobile unstuffed pajama
cases with the personality of a reckless 5 year old and fur
seal pups are small terrier puppies, bouncy and bold, then elephant
seal pups are like little old men. Very precise and somewhat
gnome-like, a stage that they grow out quite rapidly as they
become teenagers (in elephant seal years that is).

How friendly are Elephant seals?

Antarctic seals are generally completely
unafraid of man despite the inglorious days of sealing
when hundreds of thousands of them were killed fir their fur
and/or blubber. Being big, possessed of much blubber and congregating
conveniently in large numbers on beaches, elephant seals were
one of the preferred target species on an industrial scale being
killed right up until 1964 at South Georgia.

These days the recommendation is to stay
considerably further away than the man in the picture to the
right is, the small weaned pup in the foreground has just had
his very close-fitting personal space invaded and isn't that
happy - although he doesn't seem to be that bothered either
to be honest. The larger and older seals nearby seem completely
unflustered.

The only time these seals get very upset
is if you approach them walking upright. When they threaten
each other, they rear upwards to get as much height as they
can and so assume that an upright figure is being aggressive
and so is a threat. If you get down low as this guy has done,
they are pretty much unfazed, though by that time you may be
uncomfortably close to a ton or two of smelly, sharp-toothed,
animated blubber while being a bit slower off the mark as you're
now squatting down.